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A relaxed, user-friendly json-like data format.

Project description


Build Status Build Status codecov PyPI Version License: MIT

jsn is a user-friendly data format that can be easily read and reliably edited by humans.

It adds powerful features such as inheritence, variables, includes and syntax improvements to make jsn files more compact and re-usable than a json counterpart, it is an ideal solution for multi-platform build configuration, packaging and content buidling pipelines.

jsn can be used directly in python as a dictionary, or it can be converted to json to be used with other languages and tools and libraries which have json support.

If you are using hand edited json in any projects currently, jsn will easily integrate into your existing workflow and improve efficiency and reliability.


  • Includes / file import.
  • Inheritance (hierarchicle and multiple).
  • Environment style scoped variables.
  • Quoteless keys.
  • Quoteless strings.
  • Single quotes.
  • Single and multi-line comments.
  • Multi-line strings / line breaks.
  • Hex, binary, bit shifts, int and float improvements.


You can convert jsn to json using the commandline, clone this repository and add jsn to your path.

jsn -i example.jsn -o example.json -I import_dir
jsn -help
jsn ----------------------------------------------------------------------------
commandline arguments:
    -help display this message
    -i list of input files or directories to process
    -o output file or directory 
    -I list of import directories, to search for imports
    -p print output to console 

Python API

Install via pip:

python3 -m pip install jsn

Or alternatively copy where you need it.

jsn can be used just like json as a python dictionary.

import jsn
json_dict = jsn.loads(open("jsn_file.jsn", "r").read())

Example .jsn

import import.jsn
import test.jsn
    // sytax highlights quite nicely in most editors with c or c++ syntax      

    // allow comments


    //        tabs and any whitespace allowed

    // compatible with json
        "bool": true,
        "int": 1,
        "float": 1.0,
        "string": "yes",
        "array": [1, 2, 3]

    // compatible with json5
        unquoted: 'and you can quote me on that',
        single_quotes: 'I can use "double quotes" here',
        hexadecimal: 0xdecaf,
        line_breaks: "Look, Mom! No \
       leading_decimal_point: .8675309, and_trailing: 8675309.,
       positive_sign: +1,
       trailing_comma: 'in objects', and_in: ['arrays',],

    // jsn features
    	// ditch the quotes and commas!
        unquoted_string: without_whitespace // cannot contain whitespace or special chars (see str_test)
        unquoted: [strings, in, arrays]
        binary_literal: 0b10011
        bit_shifts: 1<<16 | 1<<8

        // mixed newline and commas
        object_members_separated_by_newline: {
        	no_commas: yes
        	with_new_lines: "if you like"
        	but: "you can", still: "use them here"
        	"no need for commas"
        	"if you use newlines"
        	"still", "separate", "using commas", "on the same line"

        // you can define variables to be re-used
            data: "path/to/data"
            var_str: "hello"
            var_int: 10

        // evaluate variables with ${} inside quotes..
        variable_data_path: "${data}/subdir"
        variable_int: "${var_int}"
        array_of_vars: ["${data}", "${var_str}"]

        // subobjects can be merged and inherited recursively see ** inheritence(jsn)
        base: "foo"
            one: "1"
            two: "2"
            nested_var: "${var_int}" // variable comes from outer scope.

        // use <windows, mac, linux> in angled brackets to conditionally include or exclude keys
        // the platform specific keys will be merged into the base key if one exists
            base: "exists"

        // useful for selecting platform specific paths and executables
            exe: "path/windows/program.exe"

            exe: "path/mac/program"

    inheritence(jsn): // add object name to inherit inside parenthesis
        // inheritance adds keys from 'jsn' object
        // ..

        // duplicated keys are overridden by the derived object
        base: "bar",

        // inheritance on sub-objects continues recursively
            three: "3"

    // multiple and hierarchical inheritance
    objb: { b: "b" },

    multiple_inheritence(inheritence, objb):
        // vars can also be shadowed / overriden..
            data: "another/path/to/data",
            var_int: 22

        c: "c"

        // some test cases
        empty_object: {},

        empty_array: [],

            {object: 1, other: "value"},
            {object: 2, other: "value"}


            yes: true,
                deeper: nesting

        	[2, 3]

            [hello, world],
            [goodbye, world]

            1 << 1,
            1 << 2 | 1,
            1 << 2 | 1,

            va: "path/to/data",
            vb: "hello",
        array_of_array_vars: [
        	["${va}", "${vb}"],
        	["${vb}", "non var"]

        multiple_vars: "${va}/${vb}.bin",

        q1: "small 'quotes' inside",
        q2: 'double "quotes" inside',
        q3: "double escaped \"quotes\" inside"

    str_test: ":[{}]'+.,0b0x" // this tests ignoring special chars inside quotes

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